Linux 6.15 will bring networking improvements
Linux 6.15 is currently under development with a lot of promising changes, such as better support for PlayStation 5 controllers, lots of graphics driver changes, Apple Touch Bar support, and much more to come. It also brings the following networking improvements for the core implementation:
- Continue Netlink conversions to per-namespace RTNL lock (IPv4 routing, routing rules, routing next hops, ARP ioctls).
- Continue extending the use of netdev instance locks.
- Support collecting TCP timestamps (data submitted, sent, acked) in BPF, allowing for transparent (to the application) and lower overhead tracking of TCP RPC performance.
- Tweak existing networking Rx zero-copy infra to support zero-copy Rx via io_uring.
- Optimize MPTCP performance in single subflow mode by 29%.
- Enable GRO on packets which went thru XDP CPU redirect (were queued for processing on a different CPU). Improving TCP stream performance up to 2x.
- Improve performance of contended connect() by 200% by searching for an available 4-tuple under RCU rather than a spin lock.
- Avoid unconditionally touching sk_tsflags on RX, improving performance under UDP flood by as much as 10%.
- Avoid FIB lookup in netfilter if socket is available, 20% perf win.
- Rework network device creation (in-kernel) API to more clearly identify network namespaces and their roles.
- Use sysfs_break_active_protection() instead of trylock to avoid deadlocks between unregistering objects and sysfs access.
- Add a new sysctl and sockopt for capping max retransmit timeout in TCP.
- Support masking port and DSCP in routing rule matches.
- Support dumping IPv4 multicast addresses with RTM_GETMULTICAST.
- Support specifying at what time packet should be sent on AF_XDP sockets.
- Expose TCP ULP diagnostic info (for TLS and MPTCP) to non-admin users.
- Add Netlink YAML spec for WiFi (nl80211) and conntrack.
- Introduce EXPORT_IPV6_MOD() and EXPORT_IPV6_MOD_GPL() for symbols which only need to be exported when IPv6 support is built as a module.
- Age FDB entries based on Rx not Tx traffic in VxLAN, similar to normal bridging.
- Allow users to specify source port range for GENEVE tunnels.
- netconsole: allow attaching kernel release, CPU ID and task name to messages as metadata.
After updating to Linux 6.15, you will notice improved networking performance across many areas, alongside the new features that this pull request brings. The driver API has also seen interesting improvements, such as:
- Continue rework / fixing of Energy Efficient Ethernet (EEE) across the SW layers. Delegate the responsibilities to phylink where possible. Improve its handling in phylib.
- Support symmetric OR-XOR RSS hashing algorithm.
- Support tracking and preserving IRQ affinity by NAPI itself.
- Support loopback mode speed selection for interface selftests.
In addition to that, those improvements also bring support for new device drivers, improve existing device drivers, remove the IBM LCS driver for s390, and remove the sb1000 cable modem driver.
